Gonna do some copypasta, because if I write the info, it won't get the information across any better.

From moddb:

Info posted:

Hostile Intent is all about realism, covering realistic weapon damage, realistic missions and mission stories. Hostile Intent gives the player the feeling he's actually there. Be it a nuclear submarine, an embassy raid or a military base in the middle east, each and every one of them is modelled with a level of detail that a lot of other games/mods/tc's don't have.

Amazing gameplay: The best of the best on both teams. In Hostile Intent you can either join the ranks of the world's best counter-terrorism units or be part of a member of one of the many terrorist organisations existing in the world. In the end it doesn't even matter, because in Hostile Intent you'll be fighting for your life.

Map specific player skins: Each and everyone is done with such an amount of detail and life-life animations that it makes a lot of the current retail games out look ugly. For every mission theme there is a skin set from which the mapper can choose from.

Team specific weapons arsenal: Both NATO and the Tango's have their own set of weapons to fight with. For NATO there is the MP5A4, M16A2, PSG-1 etc. The Tango's can choose from the cheap and widely available on the black market AK-47, AKSU-74, M76 etc. All the guns are balanced in such a way that there isn't one gun which is the ultimate best. Each gun has their own pro's and con's.

Extra equipment: Need a little bit more of a BANG in your attack? Grab a Fragmental Grenade. Or are you looking for a stealthy approach during the night? Better put on those Nightvision goggles. Looking for a tactical entry in that building? Grab a flashbang and take the enemy out while they're blinded.

An original take on the Half-Life VGUI: Fast and functional. No fooling around.

A realistic aiming system: The only realistic way of simulating how to aim and fire a gun. In most games you use crosshairs to aim. In Hostile Intent however, we chose to use a different way of aiming. An idea a lot of retail games are allready incorporating. Hostile Intent also uses the aim through the gun's sights as it's aiming tool. Don't worry, if you think the gun is obstructing your vision then you can just lower the weapon to waist level. This does however, seriously affects accuracy.

Basically, the game is very difficult and tedious, but that's what makes it fun. There's a large variety of weapons, but the silenced once are recommended. There is literally no HUD, only two texts saying the name of the teammate you're facing and how many magazines you have left after you reload.

At the moment, there's only one server up with about 6 people on at once. I just wanna see more people playing it. There's a source version being developed, but we only have the HL1 version for now.